Lower unit gear mesh

Froghunter

Recruit
Joined
Jan 20, 2006
Messages
3
Folks, I have 1987 Johnson 40 h.p. While in the process of servicing the water pump, I noticed that the bottom end of the driveshaft seems to be rubbing on the clutch dog. When turning the driveshaft by hand I can feel each tooth of the pinion and drive gear meshing. (feels course)If I pull the driveshaft up a very small amount while turning it, it now meshs smoothly. If this condition is due to wear, my question is what is the repair? Thank you.
 

MCM

Lieutenant Junior Grade
Joined
Jun 1, 2005
Messages
1,201
Re: Lower unit gear mesh

Welcome to the forum Froghunter,<br /><br />With the L/U bolted up and the drive shaft re connected the slack may not be there to allow for the contact that's present when disconnected.<br /><br />Just a thought :)
 

R.Johnson

Rear Admiral
Joined
Sep 24, 2003
Messages
4,446
Re: Lower unit gear mesh

When you have the gearcase off, and turning the drive shaft free hand, you can feel the pinion gear seemingly slipping in, and out of engagement. If you try this on a dry gearcase, such as after a rebuild, and before filling with oil, this is very noticeable. Keep in mind, these are bevel gears. Under power, the pinion will have some upward force, but retained by the bearings, and bearing retainer. The proper shimming maintains the correct gear lash under power, so what you feel is normal.
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: Lower unit gear mesh

what R.Johnson says. its rather normal. dont hunt for problems :) :) . enough will come along all by themselves.
 

Froghunter

Recruit
Joined
Jan 20, 2006
Messages
3
Re: Lower unit gear mesh

Thanks for the info, as a first timer, I'm impressed. I received 3 replies within one day.<br />The info I received made good sense, thanks again. :)
 
Top